Yes. I have been using them and putting alot of study into sports lately.
Your only dealing with parralels(P) and Contra Parralels(CP). The orb for these is small. Magi astrology, who makes extensive use of declinations uses an orb of 1.20 degrees. However, If there are multiple planets connecting you can extend the orb a little bit, because they have a cumulative effect. Even then, I personally like to go no higher than 2degrees. Another consideration is that declinations function like a swing. They spend more time at higher degrees and move quickly through the lower degrees. So you can use a wider orb for the lower degrees. I havent put enough research into how much you can extend that, but I wont even consider normal longitude aspects above 3degrees.
You need to look for aspects to MARS and PLUTO. Mars for the obvious reason that is represents the athlete, energy and general athleticism. Pluto represents competition, hunger, and in general strong motivations to succeed. Pluto aspects are pretty much importan to high level success at anything competitive.
Here is how I like to interpret different aspect combos, I am always evolving my ideas to pinpoint but here is where I am at.
Mars-sun= extra energy, strength, heart(metaphorical and bodily)
Mars-moon= natural instinct, natural ability, kinesthetic sense.
mars-mercury= hand eye coordination, reflexes, speed, insight into technique, skill, good tactics and smart. Respitory capacity(lungs) A.K.A, wind.
mars-venus=love of sports(more important than you would think) athletic grace, goodlooking physical body(Think boxing, individuals have more selling potential when they look the part)
Mars-jupiter=Luck in sports, extra energy, boosts overall athleticism
Mars-saturn=focus, stamina, muscular endurance, effeciency, proper use of energy as in not tomuch or not to little.
Mars-uranus=coordination, adaptibility and improvise on the fly(creativity) reflex(overlap with mecury) agility, balance, dexterity(overlap with mercury, I tend to interpret uranus as more intuitive and sudden improvement out of nowhere as opposed to the conscious learning processs that takes place with mercury)
mars-neptune=Durability, health, recovery, longevity. Note- The ability to recover is often one of the most important factors to becoming a high level athlete. The quicker you recover, the more often you train, the more progress you make both in skill and physical qualities. Hence the reason people abuse steroids, they increase testosterone which dramatically ups protein synthesis and causes healing.
mars-pluto=tons of energy, very competitive, love of sport and competition, power/explosiveness, power=speed x strength thus both are increased by this placement. determination, will to win.
mars-chiron=performance.
These are my general interps and they are open to discussion and infact I welcome it, because not many people are into sports and astrology accept as a predictive measure to make money.
You want to look for P and CP in the declinations, and Trines and conjunction in the longitudes. All aspects have an effect, but if you dont have a good number of these, or atleast tight conjunctions of the more powerful combos, then an athlete wont go far.
Super sports aspects are
Mars and any other planet
Super sports champion aspects are
Mars/pluto
mars/venus
pluto/sun
Other important aspects that give someone to be successful in general are
venus/pluto
jupiter/pluto
jupiter/uranus
uranus/pluto
As an example, Mike Tyson(Dont have birth time, so we must ignore moon and houses) June 30, 1966, Brooklyn NY.
Mike only has one useful aspect in his entire longitude chart. If you take a look he doesnt even have one useful or close aspect to his mars. However, he does have one extremely powerful conjunction of pluto/uranus seperated by 0.01 degrees. This alone however, is not enough to bring someone to the level of fame and success that he had in his career, especially when unaspected to everything else.
Now, when we look at the declinations we get a much different story. Iron Mike has Sun/mars/jupiter all within 0.28 degrees of each other. The jupiter and mars are 0.15degrees seperated. This is a powerful synchronization of 3 planets. (Btw, In magi astro, P and CP are equivilant, I dunno why but it has shown itself to be true, unless saturn is involve in the CP)
Mike also has venus/pluto within 0.44 degrees of each other.
Saturn/chiron 0.06 degree orb. Focused, disciplined performer. (Before Tysons downfall with don king, prison, that crazy wife he had, and he was with the coaches who got him to the top, he was an amazingly disciplined and technical fighter.
His mercury is also part of the venus/pluto combo and increasing it to a synchronization. Not sure how I would interpret its addition. Venus/pluto= love of compeition and success. Drive is so important in anything competitive.
I've used him as an example to illustrate that you dont always have to look for quantity of aspects, but the quality is very important. And also, declination are extremely important in assessing athletic potential. If we ignored declinations, there would be nothing to suggest athletic ability in his chart as he has no quality aspects to his mars in the longitudes.
Mike has one badass conjunction, an amazing planetary synchronization involving mars, and the super aspect venus/pluto.
Also note that, mike lacked any neptune enhancements to his sun/mars/pluto. He reached the top quick and fell out of his prime even faster.
In conclusion, Declinations ignoring declinations is ignoring half of astrology and they are very important. Mars aspects are must for an athlete, and pluto isnt far behind. Use small orbs, and look for synchronization and trines, conjunctions and eclipses(when two planets are conjunct in longitudes and P in declinations.
Anyways hope this helps.